1. Field of the Invention
The present invention relates to semiconductor modules such as a module printed circuit board (PCB) with one or more semiconductor chip packages mounted thereon, and a method of forming the semiconductor module.
2. Description of the Related Art
Recently, semiconductor modules, such as memory modules, have been widely employed in various multi-media apparatuses and digital apparatuses where the semiconductor modules have rapid response speed, low power consumption, minute sizes, etc. Generally, ball grid array (BGA) semiconductor chip packages are employed in the semiconductor modules.
The BGA semiconductor chip packages are usually divided into a micro BGA type, a wire bonding BGA (WBGA) type and a board on chip (BOC) type. A semiconductor package including a BGA is combined with a module board using solder balls instead of leads. About two to about thirty-two units of the BGA semiconductor chip packages are usually mounted on one module board.
FIGS. 1A and 1B are cross-sectional views illustrating a manual socketing procedure for a semiconductor module including conventional BGA semiconductor chip packages and a conventional printed circuit board (PCB). Referring to FIGS. 1A and 1B, a PCB 10 includes BGA semiconductor chip packages 150, such as memory chip packages, mounted thereon. As is well-known, the solders balls of the BGA semiconductor chip packages 150 are mounted to the PCB 10 forming solder joints between the PCB 10 and the BGA semiconductor chip packages 150.
The PCB 10 is socketed into a socket 20 by a manual socketing procedure. In this procedure, one or more of the BGA semiconductor chip packages 150 may be grasped by the person inserting the PCB 10 into the socket 20. This may cause a BGA semiconductor chip package 150 to become bent or twisted, and a crack in the BGA semiconductor package 150 may occur. When this happens, the electrical characteristics of the BGA semiconductor chip package 150 may decrease.
FIG. 2 is a plan view illustrating an example of a conventional BGA semiconductor package 150. As shown, the BGA semiconductor package 150 includes a BGA area in which solder balls 12 are arranged. The outermost solder balls 12 are separated from an edge of the BGA semiconductor chip package 150 by a gap of about 1 to about 3 mm. FIG. 3 is a cross-sectional view illustrating the cracking of the conventional BGA semiconductor chip package 150 when grasped. As shown, the BGA semiconductor chip package 150 may tend to crack along the outermost solder joint 14. Also, while not shown, grasping of the PCB 10 and/or the manual socketing procedure, may also result in a solder joint 14 cracking.